The current way that roaming partners and their network systems are being identified to CDMA subscriber devices is becoming unwieldy. A CDMA service provider uses system identifiers (SIDs) and optional network identifiers (NIDs) to support expansion of its CDMA network. Each SID covers a geographic area about the size of a city or large town. A NID is an optional subdivision of a SID and can identify different toll areas, rating areas, private networks, or any other subdivision a network operator may want to distinguish within a SID. A network operator may have hundreds of SID/NIDs identified in its network. A roaming partner needs to be able to store all those SID/NIDs in a preferred roaming list (PRL). This PRL is then communicated by the roaming partner network to its CDMA terminal devices and stored on the CDMA terminal devices of the roaming partner.
As SID/NIDs are changed or added on a CDMA network, roaming partners need to update their PRLs with the new SID/NIDs. The rate of introduction of new SID/NIDs has increased rapidly as CDMA carriers around the world expand and upgrade their networks. A nationwide or multi-national service provider may have many hundreds of SID/NIDs identified in its CDMA network and be continually changing its SID/NID listing.
While PRLs are getting larger, the memory available to store PRLs on a CDMA terminal device is potentially getting smaller. CDMA carriers that provide Removable User Interface Modules (RUIMs) as PRL storage space must deal with the fact that RUIMs have significantly less storage space for PRLs than non-RUIM terminal devices.
With increasing PRLs and decreasing PRL storage space, the CDMA Development Group has proposed enhancements to the PRL that will allow roaming partner networks to be identified by Mobile Country Code (MCC) and/or Mobile Network Code (MNC or IMSI—11—12) in addition to SID/NID. An advantage to this approach is that a large number of SID/NIDs in a PRL can be replaced by a single MCC/MNC in an “enhanced PRL.” Thus, by including MCC/MNCs in an enhanced PRL, the many SID/NIDs that are superseded by a single MCC/MNC can be eliminated.
A drawback to the MCC/MNC approach, however, is that it currently takes a CDMA terminal device up to two seconds to obtain MCC/MNC information from overhead channels being broadcast by a CDMA network. Thus, there is an opportunity to optimize a CDMA terminal device to handle MCC/MNC enhanced PRL entries to spend less time obtaining MCC/MNC information from overhead channels. The various aspects, features and advantages of the disclosure will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Drawings and accompanying Detailed Description.